kvm: support Rocky/RHEL/OL/Alma in the same cluster (apache#8641)

* kvm: support Rocky/RHEL/OL/Alma in the same cluster

* Update PR#8641: add unit tests

Author: weizhouapache

server/src/main/java/com/cloud/hypervisor/kvm/discoverer/LibvirtServerDiscoverer.java

@@ -62,6 +62,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
@@ -70,6 +71,10 @@
 
 public abstract class LibvirtServerDiscoverer extends DiscovererBase implements Discoverer, Listener, ResourceStateAdapter {
     private final int _waitTime = 5; /* wait for 5 minutes */
+
+    private final static HashSet<String> COMPATIBLE_HOST_OSES = new HashSet<>(Arrays.asList("Rocky", "Rocky Linux",
+            "Red", "Red Hat Enterprise Linux", "Oracle", "Oracle Linux Server", "AlmaLinux"));
+
     private String _kvmPrivateNic;
     private String _kvmPublicNic;
     private String _kvmGuestNic;
@@ -468,7 +473,7 @@ public HostVO createHostVOForConnectedAgent(HostVO host, StartupCommand[] cmd) {
             _hostDao.loadDetails(oneHost);
             String hostOsInCluster = oneHost.getDetail("Host.OS");
             String hostOs = ssCmd.getHostDetails().get("Host.OS");
-            if (!hostOsInCluster.equalsIgnoreCase(hostOs)) {
+            if (!isHostOsCompatibleWithOtherHost(hostOsInCluster, hostOs)) {
                 String msg = String.format("host: %s with hostOS, \"%s\"into a cluster, in which there are \"%s\" hosts added", firstCmd.getPrivateIpAddress(), hostOs, hostOsInCluster);
                 if (hostOs != null && hostOs.startsWith(hostOsInCluster)) {
                     logger.warn(String.format("Adding %s. This may or may not be ok!", msg));
@@ -483,6 +488,17 @@ public HostVO createHostVOForConnectedAgent(HostVO host, StartupCommand[] cmd) {
         return _resourceMgr.fillRoutingHostVO(host, ssCmd, getHypervisorType(), host.getDetails(), null);
     }
 
+    protected boolean isHostOsCompatibleWithOtherHost(String hostOsInCluster, String hostOs) {
+        if (hostOsInCluster.equalsIgnoreCase(hostOs)) {
+            return true;
+        }
+        if (COMPATIBLE_HOST_OSES.contains(hostOsInCluster) && COMPATIBLE_HOST_OSES.contains(hostOs)) {
+            s_logger.info(String.format("The host OS (%s) is compatible with the existing host OS (%s) in the cluster.", hostOs, hostOsInCluster));
+            return true;
+        }
+        return false;
+    }
+
     @Override
     public HostVO createHostVOForDirectConnectAgent(HostVO host, StartupCommand[] startup, ServerResource resource, Map<String, String> details, List<String> hostTags) {
         // TODO Auto-generated method stub

server/src/test/java/com/cloud/hypervisor/kvm/discoverer/LibvirtServerDiscovererTest.java

@@ -0,0 +1,54 @@
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+//
+
+package com.cloud.hypervisor.kvm.discoverer;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Spy;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class LibvirtServerDiscovererTest {
+
+    @Spy
+    private LibvirtServerDiscoverer libvirtServerDiscoverer;
+
+    @Test
+    public void validateCompatibleOses() {
+        validateCompatibleOs("Rocky Linux", "Rocky Linux", true);
+        validateCompatibleOs("Rocky", "Rocky Linux", true);
+        validateCompatibleOs("Red", "Red Hat Enterprise Linux", true);
+        validateCompatibleOs("Oracle", "Oracle Linux Server", true);
+        validateCompatibleOs("Rocky Linux", "Red Hat Enterprise Linux", true);
+        validateCompatibleOs("AlmaLinux", "Red Hat Enterprise Linux", true);
+
+        validateCompatibleOs("Windows", "Rocky Linux", false);
+        validateCompatibleOs("SUSE", "Rocky Linux", false);
+    }
+
+    private void validateCompatibleOs(String hostOsInCluster, String hostOs, boolean expected) {
+        if (expected) {
+            Assert.assertTrue(libvirtServerDiscoverer.isHostOsCompatibleWithOtherHost(hostOsInCluster, hostOs));
+        } else {
+            Assert.assertFalse(libvirtServerDiscoverer.isHostOsCompatibleWithOtherHost(hostOsInCluster, hostOs));
+        }
+    }
+}